A mechanical system has been realized that exhibits the topological properties of the quantum spin Hall effect (QSHE). The system, composed of 270 pendula arranged in a 9×15 lattice, demonstrates phononic edge states that are helical and topologically protected. These edge states are robust against imperfections and can function as reliable waveguides for phonons. The study shows that the physics of the QSHE can be extended from quantum systems to classical mechanical systems, opening new possibilities for the design of topological acoustic metamaterials. The QSHE in quantum systems is characterized by two counter-propagating edge modes that differ by their spin degree of freedom. These modes are protected by time-reversal symmetry and do not scatter into each other. The topological protection of edge states in mechanical systems is demonstrated by their stability against perturbations. The edge states in this mechanical system are shown to be helical, with each polarization corresponding to a chiral mode in different energy gaps. The system was designed to mimic the quantum mechanical QSHE by constructing a dynamical matrix D that incorporates the properties of the QSHE. The system was tested by exciting different frequencies and observing the response of the pendula. The results show that the edge states are robust and can be used as a polarizing beam splitter. The topological protection of the edge states is further demonstrated by their stability against boundary roughness and disorder. The study also shows that the edge states can be used to create stable acoustic delay lines and other acoustic devices. The results highlight the potential of mechanical systems in realizing topological phenomena and their applications in technology. The work bridges the gap between quantum mechanical topological insulators and mechanical systems, providing a foundation for future research in topological acoustic metamaterials.A mechanical system has been realized that exhibits the topological properties of the quantum spin Hall effect (QSHE). The system, composed of 270 pendula arranged in a 9×15 lattice, demonstrates phononic edge states that are helical and topologically protected. These edge states are robust against imperfections and can function as reliable waveguides for phonons. The study shows that the physics of the QSHE can be extended from quantum systems to classical mechanical systems, opening new possibilities for the design of topological acoustic metamaterials. The QSHE in quantum systems is characterized by two counter-propagating edge modes that differ by their spin degree of freedom. These modes are protected by time-reversal symmetry and do not scatter into each other. The topological protection of edge states in mechanical systems is demonstrated by their stability against perturbations. The edge states in this mechanical system are shown to be helical, with each polarization corresponding to a chiral mode in different energy gaps. The system was designed to mimic the quantum mechanical QSHE by constructing a dynamical matrix D that incorporates the properties of the QSHE. The system was tested by exciting different frequencies and observing the response of the pendula. The results show that the edge states are robust and can be used as a polarizing beam splitter. The topological protection of the edge states is further demonstrated by their stability against boundary roughness and disorder. The study also shows that the edge states can be used to create stable acoustic delay lines and other acoustic devices. The results highlight the potential of mechanical systems in realizing topological phenomena and their applications in technology. The work bridges the gap between quantum mechanical topological insulators and mechanical systems, providing a foundation for future research in topological acoustic metamaterials.